A monoclonal antibody toBabesia divergenswhich inhibits merozoite invasion

Abstract

A monoclonal antibody-producing hybridoma cell line has been raised against merozoites of Babesia divergens. This antibody is strongly reactive against merozoites in an enzyme-linked immunosorbent assay (ELISA) and is also positive in an indirect fluorescent antibody test (IFAT) on preparations of live merozoites. The antibody recognizes an antigen, of molecular weight (Mr) 50-60 K by Western blot analysis on SDS-polyacrylamide gel electrophoresis (SDS-PAGE) gels. Merozoite neutralization assays show that the antibody significantly inhibits merozoite invasion of bovine erythrocytes.

Identification of common surface antigens amongBabesia bigeminaisolates by using monoclonal antibodies

“…The strategy followed was to screen a panel of MAb prepared against B. bigemina for their ability to bind to surface antigens of the parasite. Surface antigens of the merozoite stage of Babesia species infecting cattle have been considered important, because of their role in eliciting the production of antibodies which may block erythrocyte invasion (Smith & Ristic, 1981;James, 1984;McElwain et al 1987;Winger et al 1987;Goff et al 1988).…”

“…The surface coat of the extraerythrocytic stage (merozoite) of Babesia bovis has been demonstrated to elicit the production of antibodies that prevent erythrocyte invasion by parasites (Smith & Ristic, 1981;James, 1984). Since the merozoite is primarily responsible for the clinical signs of the disease, identification of surface antigens of this stage may provide potential candidates to be utilized as protective immunogens against Babesia infection (McElwain et al 1987;Winger, Canning & Culverhouse, 1987;Goff et al 1988). It has, however, been demonstrated that immunological and antigenic differences existed between strains of B. bigemina (Callow, 1967;Curnow, 1973).…”

Babesia divergens , a Bovine Blood Parasite of Veterinary and Zoonotic Importance

“…Winger et al showed that an affinity-purified 50-to 60-kDa merozoite polypeptide conferred immunity to homologous challenge in gerbils (188) and that the corresponding monoclonal antibody inhibited merozoite invasion in in vitro culture (185). Later the same authors suggested that the protective antigen may represent the dimer or protein complex of another 24-to 29-kDa antigen which induced partial protection in gerbils against homologous challenge (187).…”

The adaptation of three isolates ofBabesia divergensto continuous culture in rat erythrocytes

“…Free merozoites could be obtained from cultures by differential centrifugation. Our attempts (data not given) to increase the numbers of free merozoites by CO 2 deprivation (Winger, Canning & Culverhouse, 1987) of the cultures were not successful. The free merozoites could be cryopreserved and subsequently reintroduced into culture.…”